#include<iostream>

#include<vector>



bool checkhitcircle(int x1,int y1,int x2,int y2){
	if ((( x1 - x2)*(x1 - x2) +(y1 - y2)*(y1 - y2))<400){

		return true;

	}
	else{

		return false;
	}



}



int main(){
	int throw_num;

	std::cin >> throw_num;
	std::cin.ignore();

	bool deleted_coin_vec[100000] = { false };

	std::vector<int> x_vec;
	std::vector<int> y_vec;
	int x_tmp;
	int y_tmp;
	for (int i = 0; i < throw_num; i++){
		std::cin >> x_tmp >> y_tmp;
		x_vec.push_back(x_tmp);
		y_vec.push_back(y_tmp);
		std::cin.ignore();
	}

	for (int i = 0; i < throw_num; i++){
		for (int j = 0; j < throw_num; j++){
			if (checkhitcircle(x_vec[i], y_vec[i], x_vec[j], y_vec[j])){
				deleted_coin_vec[j] = true;

			}
		}
	}

	int leave_coin_num=0;
	int deleted_coin_num=0;

	for (int i = 0;i<100000;i++){
		if (deleted_coin_vec[i]==true){
			deleted_coin_num++;
		}
	
	}
	leave_coin_num = throw_num - deleted_coin_num;

	std::cout << leave_coin_num << std::endl;


	return 0;


}